In general, the power circuit of a conventional power module and its gate driver circuit are separated; therefore, each of the power circuit and the gate driver circuit should have one packaging structure. Besides, the power circuit needs several signal buses to electrically coupled to the external gate driver circuit; therefore, the above structure will significantly increase the size of the conventional power module. For the above reasons, the conventional power module cannot be applied to light-weight vehicles or small-size machine tools, etc., which significantly limits the application range of the conventional power module.
Also, power modules are always operated in an environment with serious vibration; however, the conventional power module cannot effectively fix its components, so its chips and signal buses tend to drop off because of vibration; therefore, the failure rate of the conventional power module is very high, which significantly influences its performance.
Besides, for the purpose of achieving proper electrical-isolation and thermal-dissipation effects, the conventional power module should be processed by the thermal-dissipation paste and the electrical-isolation paste respectively; accordingly, its manufacturing process is very complicated, and needs more time and manpower, which will significantly increase its cost.
Many different power modules have been developed to solve the above problems, such as US patent publication No. 20110057713, U.S. Pat. No. 8,237,260, Taiwan patent publication No. 1478479; however, these power modules still have a lot of shortcomings to be overcome.